Before a bean to sprout, the sifting process for good beans is a very important step, i.e., every kinds of beans has to be elected with a sifting step before sprouting so as to wash out the bad beans, which may spoil the sprouting process or have bed sprouts. The conventional sifting method for beans is usually done manually, i.e., the beans are first soaked with water in a suitable container for a given period of time; then, a water pipe is inserted to the bottom of the container to provide a fast and strong water stream in the container so as to produce a whirl for washing the beans; as a result of a centrifugal force and gravity effect, the smaller and premature beans or dead beans that have less weight will float on water surface; then, a big spoon or a water pipe is used to skim or to attract the floating bad beans so as to divide beans into different classes and to obtain better sprouts.
Unfortunately, the aforesaid manual sifting method is rather slow, wasting time and manpower; further, the aforesaid washing and attracting steps done manually are merely by experience, and therefore the operation tolerance is ranging from 7-8%, as a result, a poor sprouting result would cause; in other words, it is deemed wasting time, manpower and money to the people of such business, and not conforming to economic principal.